Learning while we sleep and dream

Suppose you have a lot of information and you want to put it together so it makes sense. Here’s a suggestion from psychologists at Harvard Medical School — sleep on it.

“But remembering lots of facts is not the only or even the main function of memory,” says Walker, a sleep expert who works at Harvard-affiliated Beth Israel Deaconess Medical Center. “The key to solving problems and generating new ideas involves how those facts are put together into a bigger picture, one we’ve not seen before.”

Walker suspected that big-picture work, too, is best done on the back of sleep, at least one purpose of which is to consolidate information. He got together with Jeffrey Ellenbogen, a sleep neurologist at Brigham and Women’s Hospital, and other colleagues to test the idea.

“Our results strongly imply that sleep is actively engaged in the cognitive processing of our memories,” Ellenbogen adds. “Knowledge appears to expand both over time and with sleep.”

Walker says he likes the idea of meditation as a state “when different kinds of information cocktails are being mixed in the brain, another way of brewing new generalizations and ideas. If this is true, it opens the exciting possibility of manipulating brain states to help us solve problems and learn.”

Other research has shown that memories seem to be consolidated both during dreamless sleep at the beginning of the night and during dreams that usually occur later. How does this tie in with the conversations between hippocampus and cortex? One idea is that new memories move out of the hippocampus and into the cortex during dreamless sleep earlier in the night. When new and old memories meet, they mix in bizarre and novel ways we call dreams.